In this project, we’re using equal parts of sand and plaster to make a simple backyard foundry that’s powerful enough to melt scrap metal in seconds.
With this homemade furnace, we have the power to liquefy aluminum in the backyard and cast just about any object we can think of.
STEP 1 : THE MATERIALS NEEDED
You will need a big bag of play sand and some plaster of Paris both of which you can find at your local hardware store for under $20.
We are also going to need a 10-quart steel bucket and a tablecloth to cover anything.
For this makeshift refractory lining, we need One and 1/3 buckets full of plaster Paris or 21 cups, One and 3/4 buckets full of sand or 21 cups, and 1 and 1/4 buckets filled with water or 15 cups.
STEP 2 : MIX EVERYTHING TOGETHER
Mix everything together. It’s really important to get all the dry powder wet and work out any lumps as quickly as possible. And after mixing for a couple of minutes, it should be fairly runny and roughly all the same color.
STEP 3 : TRANSFER THE MIX
Transfer the mix to the steel bucket up to 3 inches from the top.
We use the plastic measuring bucket to form the center of the foundry.
Let the mixture dry for 3 minutes.
STEP 4 : MAKING A CUSTOM CRUCIBLE
Next step,we turn an old steel fire extinguisher into a custom crucible. Depressurize the tank and unscrewed the valve from the top to make it safe and easy to cut in half with a hacksaw.
At this point, the plaster should be pretty well set. So let’s dump the water from the bucket then use a pair of channel locks to pull the bucket out.
STEP 5 : ADDING AN AIR SUPPLY PORT
The next step is to make an air supply port . Using a 3/8 inch hole saw and a metal cutting blade, we cut a hole to accommodate the one-inch steel blower tube.
STEP 5 : INSTALLING THE BLOWER TUBE
The blower tube is made of a one-inch steel pipe, one-inch PVC coupling, and one-inch PVC pipe. Threads on one half of the coupling screw onto the steel pipe and the slip adapter on the other end simply pushes onto the PVC side easily.
STEP 6 : BUIDLING A LID
The next step is to build a lid to retain the heat. You need a couple of 4-inch U bolts. Make them stand upright in a 5-quart bucket filled with the insulating mix.
To relieve pressure buildup, make a vent hole using a 3-inch hole cutting saw.
This design works great for venting pressure and gives us the option to melt metal as well without even having to take the lid off the furnace.
By the way, if you run out of soda cans to melt, you could try using it as a blacksmithing forge or even a barbecue for summertime grilling.
We evenly place 5 charcoal briquettes at the bottom of the crucible made out of a steel fire extinguisher, which helps smelt the can faster once we fire it up.
STEP 7 : ADDING A HAIR DRYER BLOWER
A hairdryer is taped to a PVC pipe and inserted with a couple of one-inch couplings to connect the steel tube at one end and give the blower a quick release feature. This way it’s super easy to take apart and fits into a five-gallon bucket for easy storage.
The charcoal is filled it to the top and we breathe life into the steel furnace with a propane torch. The hairdryer is set to the low setting and blows a steady stream of oxygen on the charcoal to really heat things up.
The lid we made keeps the heat inside so it conserves energy while it’s bringing up the temperature. The coolest part is that the crucible lines up perfectly with the hole in the center.
The container is three inches wide, which is the perfect size for melting standard-size soda cans like these and at temperatures over 1000 degrees Fahrenheit.
In order to isolate aluminum, first, we remove the crucible making sure we have got a very secure grip with our tongs, and slowly pour the liquid into a steel mold.
The Soda cans are molded in the form of ingots. The purpose of an ingot is to keep some pure metal handy for when you want to make something cool.
Image Credits : TKOR